There are currently three main methods for medicament delivery via the respiratory tract, namely metered dose inhalers, dry powder inhalers, and nebulizers. Metered dose inhalers (“MDI”) are widely used in the management of asthma. The MDI includes a medicament packaged with a propellant in a pressurized aerosol container and can have a valve that releases a volumetric metered dose of aerosol upon actuation. Dry powder inhalers devices rely upon a burst of inspired air to fluidize and draw a dose of an active powder into the bronchial tract. Nebulizers generate an aerosol by atomizing a liquid in a carrier gas stream and require a continuous gas compressor or bulky supply of compressed gas.
Traditionally, inhalers were made of inexpensive components, but recently inhalers are being made of more expensive components such as electronically-controlled medicament drop generators. These new drop generators are expected to have a longer lifetime. However, contamination of the drop generator will present problems to long time use of the inhaler. One example of a way in which the drop generator can be contaminated is through the exhaled breath of the patient. Therefore, there is a need in the industry for an inhaler that overcomes the disadvantages of inhalers with increased lifetime.